Problem HumanEval_53 in evalplus is given as below with no contracts. A test input in evalplus is add('KKDnux', 'KDDnuxs') which gives string inputs. There are multiple test cases with string inputs for this problem.

def add(x: int, y: int):
    """Add two numbers x and y
    >>> add(2, 3)
    5
    >>> add(5, 7)
    12
    """
    return x + y